VARIABLE VALVE ACTUATING MECHANISM FOR OHV ENGINE

摘要

An OHV engine comprises a first and second cam carried by a camshaft rotatably supported by a crankcase to be rotatively actuated by a crankshaft, first and second lower rocker arms pivotally supported by a lower rocker shaft adjacent to each other, and configured to be actuated by the first and second cams, respectively, a clutch member mounted on the second rocker arm in an axially slidable and rotationally fast manner, the clutch member being axially moveable between an engaged position and a disengaged position, the clutch member being provided with an engagement recess configured to receive a corresponding engagement projection of the first lower rocker arm for a joint pivotal movement of the first and second lower rocker arms when the clutch member is at the engaged position, and an actuator for causing the clutch member to move axially between the engaged position and the disengaged position.

主权项

1. A variable valve actuating mechanism for an OHV engine, comprising:
a camshaft rotatably supported by a crankcase to be rotatively actuated by a crankshaft of the engine; a first cam carried by the camshaft; a first lower rocker arm pivotally supported by a lower rocker shaft supported by the crankcase, and configured to be actuated by the first cam at a first end thereof; a pushrod having a lower end engaged by a second end of the first lower rocker arm; an upper rocker arm pivotally supported by an upper rocker shaft supported by a cylinder head and having a first end engaged by an upper end of the pushrod; an engine valve provided in the cylinder head, and configured to be actuated by a second end of the upper rocker arm; a second cam carried by the camshaft coaxially to and adjacent to the first cam and having an at least partly greater cam profile than the first cam; a second lower rocker arm pivotally supported by the lower rocker shaft adjacent to the first lower rocker arm, and configured to be actuated by the second cam at a first end thereof; a clutch member mounted on the second rocker arm in an axially slidable and rotationally fast manner, the clutch member being axially moveable between an engaged position and a disengaged position, the clutch member being provided with an engagement feature which engages a corresponding engagement feature of the first lower rocker arm for a joint pivotal movement of the first and second lower rocker arms when the clutch member is at the engaged position; and an actuator for causing the clutch member to move axially between the engaged position and the disengaged position.